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Fiat Doblò Factory Service Manual (2000-2010)22 · Fault diagnosis
22 · Diagnostics

Engine not running smoothly / (hesistant)

Make
Fiat
Model
Doblò Factory Service Manual
Year
2000–2010
Section
Engine › Engine not running smoothly / (hesistant)
Fault diagnosisEngine not running smoothly / (hesistant)

ENGINE NOT RUNNING SMOOTHLY / (HESISTANT)

There are decreases in performance, possibly prolonged, during acceleration

Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

First check:

  • the state of the spark plugs and leads;
  • the condition of the air intake circuit
Continue to Step 1Spark plugs dirty or damagedReplace the spark plugs Op. 5510D10
Spark plug leads damagedReplace spark plug leads Op. 5510D14
Air intake circuit checkEliminate the problem
1CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket.

Verify:

  • that there are no faults in the engine management control unit
  • the plausibiilty of the parameters
Continue to Step 2'Fuel system' error appearsSee table Z50 MIXTURE STRENGTH ERROR
Another error dectected in the control unitContinue following the instructions for the diagnostic equipment
Incoherent parameterContinue following the instructions for the diagnostic equipment
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Road test the vehicle, reproducing the conditions under which the fault arises, keeping the diagnostic equipment connected

Verify:

  • that there are no faults in the engine management control unit
  • the plausibiilty of the parameters
Continue to Step 3Error arises suddenly in the control unitContinue following the instructions for the diagnostic equipment
Incoherent parameterContinue following the instructions for the diagnostic equipment
3CHECKING FUEL PRESSUREAll OKProblems metOperation

Carry out a road test, reproducing the conditions in which the fault arises.

Check the fuel supply pressure Op. 0510C10

Continue to Step 4Incorrect pressure: obstructions in the fuel delivery pipeRemove the obstructions in the fuel pipe; if necessary replace it Op. 1040B34
Incorrect pressure: tank not sufficiently ventilatedRestore tank ventilation
Pressure incorrect: fuel pump electrical circuit interruptedRepair fuel pump electrical circuit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
Pressure incorrect: fuel pump damagedReplace fuel pump assembly Op. 1040A70
4CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persists: control unit defectiveReplace control unit Op. 1056B82

There are decreases in performance, possibly prolonged, during acceleration

Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

First check:

  • the condition of the air intake circuit
Continue to Step 1Air intake circuit checkRestore correct operation of the intake circuit
1CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket.

Verify:

  • that there are no faults in the engine management control unit
  • the plausibiilty of the parameters
Continue to Step 2'Fuel system' error appearsSee table 50Z
Another error dectected in the control unitContinue following the instructions for the diagnostic equipment
Incoherent parameterContinue following the instructions for the diagnostic equipment
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Road test the vehicle, reproducing the conditions under which the fault arises, keeping the diagnostic equipment connected

Verify:

  • that there are no faults in the engine management control unit
  • the plausibiilty of the parameters
Continue to Step 3Error arises suddenly in the control unitContinue following the instructions for the diagnostic equipment
Incoherent parameterContinue following the instructions for the diagnostic equipment
3CHECKING FUEL PRESSUREAll OKProblems metOperation

Carry out a road test, reproducing the conditions in which the fault arises.

Check the fuel supply pressure Op. 0510C10

Continue to Step 4Incorrect pressure: obstructions in the fuel delivery pipeRemove the obstructions in the fuel pipe, and if necessary replace it
Incorrect pressure: tank not sufficiently ventilatedRestore tank ventilation
Pressure incorrect: fuel pump damagedReplace fuel pump assembly Op. 1040A70
4CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persists: control unit defectiveReplace engine management control unit Op. 1056B82

Parts & tools for this job For 2000 Fiat Doblò

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